A system and method for correcting phase shift in echo images are provided. The method may include one or more of the following operations. A plurality of echo images may be obtained. Homogeneous pixels in the plurality of echo images may be identified. A vector corresponding to each of at least some of the identified homogeneous pixels may be determined. A vector of a homogenous pixel includes a phase element and an amplitude element. A first complex linear model of phase shift may be determined based at least in part on the determined vectors. Phase shift of at least one of the plurality of echo images may be corrected based on the first complex linear model.

Techniques are disclosed for capturing scan data of an examination object via a magnetic resonance system. The techniques include capturing a first set of a diffusion-weighted scan data by excitation and, in an acquisition phase, acquiring a first echo signal, wherein before the acquisition phase in a diffusion preparation phase, diffusion gradients are switched for diffusion encoding of the scan data, The techniques additionally include capturing a second set of non-diffusion-weighted scan data by excitation and, in an acquisition phase, acquiring a second echo signal, wherein before the acquisition phase, in a diffusion preparation phase, the same diffusion gradients are switched as are switched for diffusion encoding of the scan data of the first set of diffusion-weighted scan data, although they have no influence on the second echo signal. Diffusion-weighted and non-diffusion-weighted scan data is thereby captured, having identical disturbances caused by eddy currents induced by switched gradients.

A system and method are provided for magnetic resonance imaging (MRI) and/or image reconstruction that includes acquiring multi-pass, chemical shift-encoded (CSE)-MRI imaging data of a subject. The method further includes performing a complex, joint estimation of phase terms in the imaging data for each pass of the multi-pass, CSE-MRI imaging data to account for concomitant gradient (CG)-induced phase errors of different passes. The method also includes generating at least one of a proton density fat fraction (PDFF) estimate or an R2* estimate that is unbiased by CG-induced phase errors using the phase terms and communicating a report that includes at least one of the PDFF estimate or the R2* estimate.

In a method and a control device for operating a magnetic resonance system by a pulse sequence that includes an excitation phase, material in an examination volume is excited by emission of an RF excitation pulse during a selection gradient pulse in a first gradient direction. RF refocusing pulses are then emitted and readout gradient pulses are activated in a second gradient direction for spatially coded acquisition of raw data of the examination volume along the second gradient direction. A prephasing gradient pulse is switched before a first RF refocusing pulse in the second gradient direction, and/or a rephaser gradient pulse is switched before an RF restore pulse, following the RF refocusing pulses, in the second gradient direction. The prephaser gradient pulse and/or the rephaser gradient pulse have lower slew rates than the readout gradient pulses.

A computer-implemented method for performing spatiotemporal background phase correction for phase contrast velocity encoded magnetic resonance imaging includes performing a phase contrast magnetic resonance imaging scan of a region of interest within a patient to yield a complex image and calculating a plurality of filter cut-off frequencies based on physiological limits associated with the patient. A spatiotemporal filter is created based on the plurality of filter cut-off frequencies. This spatiotemporal filter is applied to the complex image to yield a low-pass filtered complex image. Then, complex division is performed using the complex image and the low-pass filtered complex image to yield a corrected image.

Methods for automatically compensating eddy currents in a magnetic resonance apparatus include determining modified magnetic resonance sequence data by a compensation computing unit and performing a magnetic resonance measurement in which a gradient generating system generates magnetic field gradients based on the modified magnetic resonance sequence data. The determining of the modified magnetic field gradient includes: receiving original magnetic resonance sequence data of a predetermined magnetic resonance sequence; computing eddy current information about eddy currents that would be produced in the magnetic resonance apparatus by applying the original magnetic resonance sequence data; computing, based on the computed eddy current information, at least one eddy current compensation gradient pulse for compensating the eddy currents; generating modified magnetic resonance sequence data by inserting the at least one eddy current compensation gradient pulse into the original magnetic resonance sequence data; and outputting the modified magnetic resonance sequence data to the gradient generating system.

A magnetic resonance imaging method, a magnetic resonance imaging system, and a computer-readable storage medium are provided. The magnetic resonance imaging method comprises: acquiring a plurality of portions of a k-space by using a plurality of sets of imaging sequences to obtain a plurality of k-space data sets, each set of imaging sequences comprising a pre-dephasing gradient pulse and a plurality of phase encoding gradients applied after the pre-dephasing gradient pulse, wherein the pre-dephasing gradient pulses in the plurality of sets of imaging sequences have a standard area difference in order when sorted according to the sizes of area values, and the standard area difference is 2/N of the area of any phase encoding gradient, where N is the number of sets of the plurality of sets of imaging sequences; respectively reconstructing a magnetic resonance image from each of the plurality of k-space data sets; and processing the plurality of k-space data sets to obtain a magnetic resonance image.

A magnetic resonance imaging system and method, and a computer-readable storage medium are provided. The magnetic resonance imaging method includes: acquiring a plurality of k-space data sets by using a plurality of imaging sequences, each imaging sequence comprising a pre-phase-dispersion gradient pulse and a plurality of phase encoding gradients applied after the pre-phase-dispersion gradient pulse, wherein the pre-phase-dispersion gradient pulses of the plurality of imaging sequences have a standard area difference therebetween when ordered according to area values; respectively reconstructing magnetic resonance images from the respective k-space data sets; and averaging amplitudes of the magnetic resonance images to generate a magnetic resonance image of an average amplitude.

In some aspects, a magnetic system for use in a low-field MRI system. The magnetic system comprises at least one electromagnet configured to, when operated, generate a magnetic field to contribute to a B.sub.0 field for the low-field MRI system, and at least one permanent magnet to produce a magnetic field to contribute to the B.sub.0 field.

In a method for displaying quantitative magnetic resonance image data, and a processor, and a magnetic resonance (MR) apparatus that implement such a method, first quantitative MR image data of an examination object are provided to the processor, the first quantitative MR image having been obtained using an MR scanner with a first basic magnetic field strength. The first quantitative magnetic resonance image data are converted in the processor from the first basic magnetic field strength to a second basic magnetic field strength, thereby generating second quantitative MR image data, which are then displayed.